that's very odd and it might not be mezz's fault. in my experience mezz uses very high quality shaft wood and their cues are some of the straightest i've seen. if this guy's mezz's were all warped, did you not consider it might be his fault? if you leave your stock to roast in the trunk of the car on a hot sunny day or something like that, it's gonna warp no matter who made it.
Tap, Tap Tap...
I have about 4 Wd700's and 1 HP1, all of the shafts are fine... in fact more straight that most, try keeping your Humidity about 40% all the time... this should help imensly